The original SOFT_DISABLE patches didn't add support for soft disable of syscall events; this adds it and paves the way for future patches allowing triggers to be added to syscall events, since triggers are built on top of SOFT_DISABLE.
Add an array of ftrace_event_file pointers indexed by syscall number to the trace array alongside the existing enabled bitmaps. The ftrace_event_file structs in turn contain the soft disable flags we need for per-syscall soft disable accounting; later patches add additional 'trigger' flags and per-syscall triggers and filters. Signed-off-by: Tom Zanussi <[email protected]> --- kernel/trace/trace.h | 2 ++ kernel/trace/trace_syscalls.c | 14 ++++++++++++++ 2 files changed, 16 insertions(+) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 4a4f6e1..af6eb2c 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -202,6 +202,8 @@ struct trace_array { int sys_refcount_exit; DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls); DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls); + struct ftrace_event_file *enter_syscall_files[NR_syscalls]; + struct ftrace_event_file *exit_syscall_files[NR_syscalls]; #endif int stop_count; int clock_id; diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 322e164..4915b69 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -302,6 +302,7 @@ static int __init syscall_exit_define_fields(struct ftrace_event_call *call) static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) { struct trace_array *tr = data; + struct ftrace_event_file *ftrace_file; struct syscall_trace_enter *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; @@ -317,6 +318,10 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) if (!test_bit(syscall_nr, tr->enabled_enter_syscalls)) return; + ftrace_file = rcu_dereference_raw(tr->enter_syscall_files[syscall_nr]); + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) + return; + sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) return; @@ -345,6 +350,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) { struct trace_array *tr = data; + struct ftrace_event_file *ftrace_file; struct syscall_trace_exit *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; @@ -359,6 +365,10 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) if (!test_bit(syscall_nr, tr->enabled_exit_syscalls)) return; + ftrace_file = rcu_dereference_raw(tr->exit_syscall_files[syscall_nr]); + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) + return; + sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) return; @@ -397,6 +407,7 @@ static int reg_event_syscall_enter(struct ftrace_event_file *file, if (!tr->sys_refcount_enter) ret = register_trace_sys_enter(ftrace_syscall_enter, tr); if (!ret) { + rcu_assign_pointer(tr->enter_syscall_files[num], file); set_bit(num, tr->enabled_enter_syscalls); tr->sys_refcount_enter++; } @@ -416,6 +427,7 @@ static void unreg_event_syscall_enter(struct ftrace_event_file *file, mutex_lock(&syscall_trace_lock); tr->sys_refcount_enter--; clear_bit(num, tr->enabled_enter_syscalls); + rcu_assign_pointer(tr->enter_syscall_files[num], NULL); if (!tr->sys_refcount_enter) unregister_trace_sys_enter(ftrace_syscall_enter, tr); mutex_unlock(&syscall_trace_lock); @@ -435,6 +447,7 @@ static int reg_event_syscall_exit(struct ftrace_event_file *file, if (!tr->sys_refcount_exit) ret = register_trace_sys_exit(ftrace_syscall_exit, tr); if (!ret) { + rcu_assign_pointer(tr->exit_syscall_files[num], file); set_bit(num, tr->enabled_exit_syscalls); tr->sys_refcount_exit++; } @@ -454,6 +467,7 @@ static void unreg_event_syscall_exit(struct ftrace_event_file *file, mutex_lock(&syscall_trace_lock); tr->sys_refcount_exit--; clear_bit(num, tr->enabled_exit_syscalls); + rcu_assign_pointer(tr->exit_syscall_files[num], NULL); if (!tr->sys_refcount_exit) unregister_trace_sys_exit(ftrace_syscall_exit, tr); mutex_unlock(&syscall_trace_lock); -- 1.7.11.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
